Statesman is an opinionated state machine library designed to provide a robust audit trail and data integrity. It decouples the state machine logic from the underlying model and allows for easy composition with one or more model classes.

Automatically "hires" and "fires" (aka "scales") Delayed Job and Resque workers on Heroku. When there are no queue jobs, HireFire will fire (shut down) all workers. If there are queued jobs, then it'll hire (spin up) workers.

With hstore you can add schema-less data to PostgreSQL. This allows you to store model attributes without creating separate database columns. Watch how to do this using the activerecord-postgres-hstore gem.